A stiffened petticoat or underskirt made with this material, designed to support the skirts of a woman's dress; (hence) a rigid petticoat worn for this purpose, lined with, or consisting of, a framework of some other material, as whalebone, steel hoops, etc.; a hoop petticoat. It enjoyed greatest popularity in the mid 19th cent [OED] Below is a cutaway view of a crinoline, Punch magazine, August 1856

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